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Abstract:

An adjustable coaxial needle assembly for placement into a tissue mass
prior to a biopsy procedure comprises a guide cannula assembly, a stylet,
and a throw calibrator. The stylet is selectively coaxially received by
the guide cannula, which is in turn coaxially received by the throw
calibrator. The effective length of the guide cannula can be selectively
adjusted by moving the throw calibrator relative to the guide cannula to
adjust the distance between an open distal end of the guide cannula and a
the throw calibrator.

Claims:

1. A coaxial needle assembly, comprising:a cannula defining a lumen and
having a proximal end and a distal end;a stylet removably received within
the lumen and having a proximal end and a distal end; anda throw
calibrator adjustably carried by the cannula and having a biopsy device
insertion stop;wherein the throw calibrator may be used to adjust the
position of the insertion stop relative to the cannula to calibrate the
coaxial needle assembly with the throw distance of a biopsy device.

2. The coaxial needle assembly according to claim 1 wherein the throw
calibrator comprises an elongated slot and the cannula has a detent that
is received in the slot to permit relative longitudinal movement between
the throw calibrator and the cannula, whereby the length of the elongated
slot determines the range of movement of the throw calibrator relative to
the cannula.

3. The coaxial needle assembly according to claim 2 wherein the length of
the elongated slot is selected such that the range of movement of the
throw calibrator relative to the cannula corresponds to the range of
possible throw distances of a biopsy device.

4. The coaxial needle assembly according to claim 1 wherein the throw
calibrator further comprises a releasable lock to releasbly fix the
position of the insertion stop along the cannula.

5. The coaxial needle assembly according to claim 4 wherein the releasable
lock comprises a torsion spring carried by the throw calibrator and
encircling the cannula.

6. The coaxial needle assembly according to claim 1 wherein the throw
calibrator comprises a cylindrical body that encircles the cannula and
slidably moves relative to the cannula.

7. The coaxial needle assembly according to claim 6 wherein the
cylindrical body comprises a proximal end that forms the insertion stop.

8. The coaxial needle assembly according to claim 7 wherein the slidable
adjustment of the cylindrical body adjusts the effective length between
the proximal end of the cylindrical body and the distal end of the
cannula.

9. The coaxial needle assembly according to claim 8 wherein the
cylindrical body comprises indicia that correspond to the throw distance
of a biopsy device such that the indicia can be used to calibrate the
coaxial needle assembly with the throw distance of a biopsy device.

10. The coaxial needle assembly according to claim 1 wherein the cannula
further comprises a cannula hub attached to the proximal end of the
cannula and the stylet further comprises a stylet hub attached to the
proximal end of the stylet and the stylet hub is releasably coupled with
the cannula hub.

11. The coaxial needle assembly according to claim 10 wherein the stylet
hub and the cannula hub are releasably coupled by a luer lock coupling.

12. The coaxial needle assembly according to claim 1 wherein the throw
calibrator is infinitely adjustable.

13. The coaxial needle assembly according to claim 1 wherein the throw
calibrator comprises indicia that correspond to the throw distance of a
biopsy device such that the indicia can be used to calibrate the coaxial
needle assembly with the throw distance of a biopsy device.

14. A biopsy device system for the percutaneous removal of a specimen from
an area of interest within a tissue mass, the biopsy device system
comprising:a variable throw biopsy device having a needle assembly with
an adjustable throw distance;a guide cannula defining a lumen and having
a proximal end and a distal end; anda throw calibrator adjustably carried
by the guide cannula and having a biopsy device insertion stop;wherein
the throw calibrator may be used to adjust the position of the insertion
stop relative to the guide cannula to calibrate the guide cannula with
the throw distance of the biopsy device.

15. The biopsy device system according to claim 14 and further comprising
a tip protector defining a lumen, wherein the tip protector is removably
received on the guide cannula with the guide cannula extending through
the lumen of the tip protector.

16. The biopsy device system according to claim 15 and further comprising
at least one passageway for the flow of sterilization fluid between the
tip protector and the guide cannula.

17. The biopsy device system according to claim 14 and further comprising
a stylet removably received within the lumen and having a proximal end
and a distal end, wherein the stylet and the guide cannula together form
a coaxial needle assembly when the stylet is received within the lumen.

18. The biopsy device system according to claim 17 wherein the guide
cannula further comprises a cannula hub attached to the proximal end of
the cannula and the stylet further comprises a stylet hub attached to the
proximal end of the stylet and the stylet hub is releasably coupled with
the cannula hub.

19. The biopsy device system according to claim 14 wherein the position of
the insertion stop relative to the distal end calibrates the effective
length of the guide cannula with the throw distance of a biopsy device.

20. The biopsy device system according to claim 19 wherein the range of
movement of the insertion stop relative to the cannula corresponds to the
range of possible throw distances of the biopsy device.

21. A method for inserting a variable throw biopsy device into a tissue
mass, the method comprising:setting the throw distance of the biopsy
device;calibrating the effective length of a guide cannula in accordance
with the throw distance;inserting the guide cannula into the tissue mass;
andinserting the biopsy device into the guide cannula.

22. The method according to claim 21 and further comprising removing a
stylet from the guide cannula after inserting the guide cannula into the
tissue mass but before inserting the biopsy device into the guide
cannula.

23. The method according to claim 22 wherein removing the stylet comprises
unlocking the stylet from the guide cannula and axially withdrawing the
stylet from the guide cannula

24. The method according to claim 22 wherein calibrating the effective
length of the guide cannula comprises setting the distance between a
distal end of the cannula and a biopsy device insertion stop carried on
the guide cannula.

25. The method according to claim 24 wherein calibrating the effective
length of the guide cannula comprises sliding the guide cannula over the
needle assembly and axially moving the guide cannula relative to the
needle assembly to a position in which the guide cannula and the needle
assembly are in a predetermined relationship for insertion into the
tissue mass.

26. The method according to claim 24 wherein inserting the biopsy device
into the guide cannula comprises inserting the biopsy device until it
meets the insertion stop.

27. The method according to claim 26 and further comprising inserting a
stylet into the guide cannula after calibrating the effective length of
the guide cannula but before inserting the guide cannula into the tissue
mass.

28. The method according to claim 21 wherein calibrating the effective
length of the guide cannula comprises setting the distance between a
distal end of the cannula and a biopsy device insertion stop carried on
the guide cannula.

29. The method according to claim 28 wherein inserting the biopsy device
into the guide cannula comprises inserting the biopsy device until it
meets the insertion stop.

30. The method according to claim 28 wherein calibrating the effective
length of the guide cannula comprises adjusting the position of the
insertion stop on the guide cannula

31. The method according to claim 21 wherein calibrating the effective
length of the guide cannula comprises sliding the guide cannula over the
needle assembly and axially moving the guide cannula relative to the
needle assembly to a position in which the guide cannula and the needle
assembly are in a predetermined relationship for insertion into the
tissue mass.

32. The method according to claim 31 wherein the predetermined
relationship comprises a distal end of the needle assembly closing an
open distal end of the guide cannula.

33. The method according to claim 31 and further comprising inserting a
stylet into the guide cannula after calibrating the effective length of
the guide cannula but before inserting the guide cannula into the tissue
mass.

34. The method according to claim 21 wherein calibrating the effective
length of the guide cannula comprises setting the effective length
according to indicia provided on the guide cannula.

35. A method for calibrating a guide cannula for use with a biopsy device
having a needle assembly, the method comprising:determining the throw
distance of the biopsy device; andadjusting the effective length of a
guide cannula in accordance with the throw distance to maintain a
predetermined relative relationship between the guide cannula and the
needle assembly when the biopsy device is received within the guide
cannula.

36. The method according to claim 35 and further comprising sliding the
guide cannula over the needle assembly prior to adjusting the effective
length of the guide cannula.

37. The method according to claim 36 wherein adjusting the effective
length of the guide cannula comprises axially moving the guide cannula
relative to the needle assembly to a position in which the guide cannula
and the needle assembly are in a predetermined relationship for insertion
into the tissue mass.

38. The method according to claim 37 wherein the predetermined
relationship comprises a distal tip of the needle assembly closing an
open distal end of the guide cannula.

39. The method according to claim 37 wherein the predetermined
relationship comprises a distal tip of the needle assembly flush with an
open distal end of the guide cannula.

40. The method according to claim 35 wherein adjusting the effective
length of the guide cannula comprises setting the effective length
according to indicia provided on the guide cannula and calibrated with
the throw distance of the biopsy device.

41. The method according to claim 35 wherein adjusting the effective
length of the guide cannula comprises setting the distance between a
distal end of the cannula and a biopsy device insertion stop carried on
the guide cannula.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This application claims the benefit of U.S. Provisional Patent
Application No. 60/949,966, filed Jul. 16, 2007, which is incorporated
herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]In one aspect, the invention relates to a coaxial needle assembly
for the placement of a cannula within a tissue prior to a biopsy
procedure.

[0004]2. Description of the Related Art

[0005]A biopsy is a well-known medical procedure that involves taking a
sample of tissue from a person and examining it for diagnostic purposes.
The biopsy is often done when an abnormality, such as a lesion, is found
in a tissue mass, using an imaging system, such as mammography or
ultrasonography, or other methods of detection. While biopsies can be
used for many different purposes, examining a sample of tissue from an
abnormal site is one way to accurately diagnose whether the site is
cancerous. In the case of suspected cancer, particularly cancer of the
breast, early detection and diagnosis is critical to the success of the
patient's treatment and recovery.

[0006]One biopsy technique frequently performed is a core biopsy, which
uses a biopsy device in which a tissue specimen is captured in a coring
cannula that is advanced into the tissue mass to the site of the
abnormality. Some biopsy devices use a notched biopsy stylet that is
inserted into a lesion, such that tissue prolapses into the notch on the
biopsy stylet, with the coring cannula then advancing over the notch to
cut a tissue sample. Other devices use just a coring cannula, which
requires moving the end of the coring cannula to effect severing of the
tissue sample from the surrounding tissue mass. Another device advances a
spoon into the tissue mass, which is then followed by a coring cannula
having a cutting finger, which is rotated to sever the tissue sample.
Such a device can be found in commonly assigned U.S. Patent Application
Publication No. 2006/0030785, entitled "Core Biopsy Device", which is
incorporated herein by reference in its entirety. The biopsy cannula and
stylet, if used, with the tissue sample, is then removed from the tissue,
and the tissue sample is examined.

[0007]It is often necessary to take multiple tissue samples from the
lesion and/or the surrounding area. To avoid having to puncture the skin
for every tissue sample, a coaxial needle assembly is placed in the
tissue prior to use of the biopsy device to act as a guide for the biopsy
device. A coaxial needle assembly commonly includes a needle cannula
defining a lumen in which a stylet is received to close off the open
distal end of the needle cannula during insertion to prevent unwanted
coring of the tissue. After insertion, the stylet is removed and the
biopsy cannula and stylet/spoon of the biopsy device are inserted through
the needle cannula and into the lesion to take a tissue sample. The
biopsy device is then removed from the tissue, and the needle cannula can
be manipulated to a new location within the tissue mass so that upon
reinsertion of the biopsy device, a tissue sample can be taken from a
different area of or surrounding the lesion.

[0008]The coaxial needle assembly is commonly placed using an imaging
device. The placement normally locates the tip of the needle cannula at
the desired location relative to the lesion. The biopsy device and needle
cannula can be configured such that the biopsy device is aligned relative
to the needle cannula to insure that upon actuation of the biopsy device,
the biopsy specimen will be taken at a known distance from the tip of the
needle cannula. A common way of accomplishing the alignment is to insert
the biopsy device into the needle cannula until the biopsy device aligns
with a reference point on the needle cannula. This can be done by
aligning marks on the biopsy device and needle cannula or by inserting
the biopsy device until it abuts the needle cannula. In most cases, the
tip of the biopsy device's cannula/stylet is aligned with the tip of the
needle cannula when the biopsy device and needle cannula are aligned. The
reference points are external of the tissue mass, whereas the tips of the
biopsy device and needle cannula are internal of the tissue mass, which
provides the user with an externally visual method of aligning the
internal tips, which are not visible other than using an imagining
device.

[0009]The position of the needle cannula determines what tissue will be
sampled by the biopsy device, since the biopsy cannula will protrude from
the end of the needle cannula to take a tissue sample. Therefore, for
current systems the alignment is dependent on the length of the needle
cannula being the same as or a fixed length relative to the biopsy
cannula prior to taking a tissue sample.

[0010]The current alignment approach is not compatible with biopsy devices
having adjustable length biopsy specimens, especially those that increase
the relative length of the cannula or stylet to adjust the length of the
specimen. If the length of the biopsy device's cannula or stylet is
extended/retracted relative to the supporting body to effect the specimen
length adjustment and the abutment of the supporting body with the needle
cannula is used for alignment, the biopsy device's cannula or stylet will
be over/under inserted relative to the cannula needle. As such, it
becomes necessary to account for the difference in lengths between the
biopsy cannula and stylet and the needle cannula, which has a fixed
length. This is difficult, since the user cannot view the position of the
cannulas within the body and must rely upon external cues to verify that
the biopsy cannula is correctly positioned within the needle cannula.

[0011]Another issue is that manufacturers of biopsy devices and coaxial
needle assemblies often have unique ways of measuring the length of their
respective cannulas. It is therefore difficult to use one manufacturer's
biopsy device with another manufacturer's coaxial needle assembly.

SUMMARY OF THE INVENTION

[0012]In accordance with one aspect of the invention, a coaxial needle
assembly comprises a cannula defining a lumen and having a proximal end
and a distal end, a stylet removably received within the lumen and having
a proximal end and a distal end, and a throw calibrator adjustably
carried by the cannula and having a biopsy device insertion stop, wherein
the throw calibrator may be used to adjust the position of the insertion
stop relative to the cannula to calibrate the coaxial needle assembly
with the throw distance of a biopsy device.

[0013]In accordance with another aspect of the invention, a biopsy device
system for the percutaneous removal of a specimen from an area of
interest within a tissue mass is disclosed. The biopsy device system
comprises a variable throw biopsy device having a needle assembly with an
adjustable throw distance, a guide cannula defining a lumen and having a
proximal end and a distal end, and a throw calibrator adjustably carried
by the guide cannula and having a biopsy device insertion stop, wherein
the throw calibrator may be used to adjust the position of the insertion
stop relative to the guide cannula to calibrate the guide cannula with
the throw distance of the biopsy device.

[0014]In accordance with yet another aspect of the invention, a method for
inserting a variable throw biopsy device into a tissue mass is disclosed.
The method comprises setting the throw distance of the biopsy device,
calibrating the effective length of a guide cannula in accordance with
the throw distance, inserting the guide cannula into the tissue mass, and
inserting the biopsy device into the guide cannula.

[0015]In accordance with still another aspect of the invention, a method
for calibrating a guide cannula for use with a biopsy device having a
needle assembly is disclosed. The method comprises determining the throw
distance of the biopsy device and adjusting the effective length of a
guide cannula in accordance with the throw distance to maintain a
predetermined relative relationship between the guide cannula and the
needle assembly when the biopsy device is received within the guide
cannula.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]In the drawings:

[0017]FIG. 1 is a perspective view of a coaxial needle assembly comprising
a cannula assembly, a stylet assembly, and a throw calibrator according
to a first embodiment of the invention.

[0018]FIG. 2 is an exploded view of the coaxial needle assembly from FIG.
1.

[0019]FIG. 3 is a close-up cross-sectional view of the cannula assembly
from FIG. 1.

[0020]FIG. 4 is a close-up cross-sectional view of the stylet assembly
from FIG. 1.

[0021]FIG. 5 is a close-up cross-sectional view of the throw calibrator
from FIG. 1.

[0022]FIGS. 6A-6B are cross-sectional views through the coaxial needle
assembly from FIG. 1, illustrating the movement of the throw calibrator
along the cannula assembly.

[0023]FIG. 7A is a cross-sectional view of the coaxial needle assembly
inserted into a tissue mass having a lesion.

[0024]FIG. 7B is a cross-sectional view of the coaxial needle assembly
inserted into the lesion in the tissue mass.

[0025]FIG. 7C is a cross-sectional view of the stylet assembly of the
coaxial needle assembly withdrawn from the tissue mass, leaving the
cannula assembly and throw calibrator in place.

[0026]FIG. 7D is a cross-sectional view of a biopsy device inserted into
the coaxial needle assembly.

[0027]FIG. 8 is a perspective view of a biopsy device system comprising
the coaxial needle assembly from FIG. 1 inserted to the lesion and a
biopsy device comprising a biopsy needle assembly for obtaining a biopsy
sample from the lesion by inserting the needle assembly through the
cannula assembly.

[0028]FIGS. 9A-9B are cross-sectional views through the biopsy device
system from FIG. 8, with the coaxial needle assembly received on the
biopsy device to calibrate the coaxial needle assembly with the throw
distance of the biopsy device.

[0029]FIG. 10 is a perspective view of a coaxial needle assembly
comprising a cannula assembly, a stylet assembly, and a throw calibrator
according to a second embodiment of the invention.

[0030]FIG. 11 is an exploded view of the coaxial needle assembly from FIG.
9.

[0031]FIG. 12 is a perspective view of the coaxial needle assembly from
FIG. 9 with a distal tip protector disposed on the throw calibrator.

[0032]FIG. 13A is a close-up perspective view of a luer lock coupling for
the cannula assembly and stylet assembly in an uncoupled or unlocked
position.

[0033]FIG. 13B is a close-up perspective view of the luer lock coupling in
a coupled or locked position.

[0034]FIG. 14 is a perspective view of a biopsy device system comprising
the coaxial needle assembly from FIG. 10 inserted to the lesion and a
biopsy device comprising a biopsy needle assembly for obtaining a biopsy
sample from the lesion by inserting the needle assembly through the
cannula assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035]Referring to FIGS. 1-2, a coaxial needle assembly 10 according to a
first embodiment of the invention is illustrated, and comprises a cannula
assembly 12, a stylet assembly 14, and an adjustable body comprising a
throw calibrator 16 that is used to calibrate the coaxial needle assembly
10 with the throw of a biopsy device. The stylet assembly 14 is
selectively coaxially received by the cannula assembly 12, which is in
turn selectively coaxially received by the throw calibrator 16. As used
herein with respect to the coaxial needle assembly 10, the terms "distal"
and "forward" refer to or in a direction toward that end of the coaxial
needle assembly 10 that is directed toward a lesion and away from a user.
"Proximal" or "rearward" thus refers to or in a direction toward that end
of the coaxial needle assembly 10 that is directed away from the lesion
and toward the user. It is also understood that some of the drawings are
not to scale, in order to clearly illustrate the various features of the
invention.

[0036]Referring to FIGS. 1-3, the cannula assembly 12 comprises a guide
cannula 18 defining a lumen 20 and having an open distal end 22 and an
open proximal end 24. A cannula hub 26 is attached to the outer surface
of the guide cannula 18 near the open proximal end 24. The cannula hub 26
comprises a cylindrical body 28 having a rearward end wall 30 and a
forward end wall 32, and a hollow interior 34 extending though the
cylindrical body 28 to accommodate the guide cannula 18 and the stylet
assembly 14.

[0037]The cylindrical body 28 includes a proximal section 36 joined to a
distal section 38 that is of slightly greater diameter than the proximal
section 36 to form a stylet hub engaging surface 40 that faces
rearwardly. A pair of opposing rearward end flanges 42 extend partially
around the periphery of the proximal section 36, adjacent the rearward
end wall 30, and a forward end flange 44 extends around the periphery of
the distal section 38, adjacent the forward end wall 44. A flexible
detent 46 is formed on the forward end flange 44 and projects distally of
the forward end wall 32.

[0038]Referring to FIGS. 1-2 and 4, the stylet assembly 14 comprises a
needle or stylet 48 having a distal end 50 defining an insertion tip 52
and a proximal end 54. A stylet hub 56 is attached to the stylet 48 near
the proximal end 54 and can be releasably coupled with the cannula hub
26. The stylet hub 56 comprises a proximal handle section 58, which a
user can grip to manipulate the stylet assembly 14, joined with a distal
receiving section 60 having a hollow interior 62 which receives the
proximal section 36 of the cannula hub 36 and a forward end wall 63. The
hollow interior 62 comprises screw threads 64 that are engaged by the
rearward end flange 42 by rotating the proximal section 36 within the
hollow interior 62 to releasably fasten the stylet assembly 14 to the
cannula assembly 12.

[0039]Referring to FIGS. 1-2 and 5, the throw calibrator 16 comprises
generally cylindrical body that encircles the guide cannula 18 and can
slidably move relative to the guide cannula 18. The throw calibrator can
comprise an insertion stop 66 for arresting the insertion of a biopsy
device needle assembly into a tissue mass. By adjusting the position of
the insertion stop 66 relative to the cannula assembly 12 (in this case
by axially moving the throw calibrator 16), the coaxial needle assembly
10 can be calibrated with the throw of a biopsy device.

[0040]As illustrated herein, the throw calibrator 16 comprises a proximal
or rearward end wall 66 that acts as the insertion stop 66, a distal or
forward end wall 68, and a hollow interior 70 extending though the throw
calibrator 16 to accommodate the cannula assembly 12 and the stylet
assembly 14. The throw calibrator 16 includes a proximal cylindrical
section 72 joined to a distal nose section 74 that has a smaller diameter
than the cylindrical section 72. An elongated slot 76 is formed on the
cylindrical section 72 and slidingly receives the detent 46 on the
cannula assembly 12 to prevent the cannula assembly 12 from rotating with
respect to the throw calibrator 16 and to guide the longitudinal movement
of the cannula assembly 12 relative to the throw calibrator 16. The
length of the elongated slot 76 further determines the range of movement
of the throw calibrator 16 relative to the cannula assembly 12. The
length of the elongated slot 76 can selected such that the range of
movement of the throw calibrator 16 corresponds to the range of possible
throw distances of a biopsy device.

[0041]The hollow interior 70 of the throw calibrator 16 receives a
releasable lock that fixes the position of the throw calibrator 16 in
relation to the cannula assembly 12, and, as illustrated herein, includes
a torsion spring 78 having spring arms 80 that protrude through an
opening 82 formed in the nose section 74. When assembled, the guide
cannula 18 is slidably received through the torsion spring 78 to
releasably fix the position of the throw calibrator 16 along the guide
cannula 18. Squeezing the spring arms 80 releases the torsion spring 78
relative to the guide cannula 18, permitting the throw calibrator 16 to
be slid along the guide cannula 18 until the spring arms 80 are released.

[0042]Referring to FIGS. 6A-6B, the coaxial needle assembly 10 can be
calibrated with the throw distance of a biopsy device by moving the throw
calibrator 16 relative to the cannula assembly 12. This adjusts the
effective length of the guide cannula 18, which is the distance between
the open distal end 22 and the insertion stop 66 of the throw calibrator
16. This also adjusts the distance the stylet 48 protrudes with respect
to the throw calibrator 16, since the insertion of the stylet 48 within
the guide cannula 18 is limited by the abutment of the forward end wall
63 against the stylet hub engaging surface 40. The effective length of
the guide cannula 18 is adjusted by pressing the spring arms 80 toward
each other to expand the torsion spring 78 and loosen its grip on the
guide cannula 18, allowing the throw calibrator 16 to be translated along
the cannula assembly 12. The range of movement of the throw calibrator 16
relative to the cannula assembly 12 is limited by the length of the slot
76 in which the detent 46 moves. As shown in FIG. 6A, the guide cannula
18 is at a minimum effective length in the position where the detent 46
abuts the forward portion of the slot 76. As shown in FIG. 6B, the guide
cannula 18 is at a maximum effective length in the position where the
detent 46 abuts the rearward portion of the slot 76. It is understood
that the effective length of the guide cannula 18 is infinitely
adjustable between the positions illustrated in FIGS. 6A-6B because the
position of the throw calibrator 16 is infinitely adjustable. It is also
understood that the cannula assembly 12 and stylet assembly 14 can be
moved as a unit, while keeping the throw calibrator 16 relatively still.
The throw calibrator 16, or another portion of the coaxial needle
assembly 10, can further be provided with indicia (not shown), such as
distance markings or a digital display, for enabling the length of
coaxial needle assembly 10 to be adjusted a predetermined distance.

[0043]FIG. 8 illustrates one example of a biopsy device system for the
percutaneous removal of a specimen from an area of interest within a
tissue mass 100, in which the coaxial needle assembly 10 is used in
conjunction with a biopsy device 300. An exemplary biopsy device 300
comprises a actuator assembly 302 structurally and operably connected to
a biopsy needle assembly 304 which is used to penetrate the tissue mass
100 to obtain a biopsy sample from an area of interest comprising a
lesion 200. The biopsy needle assembly 304 includes a biopsy cannula 306
and a biopsy stylet 308 which is received by the biopsy cannula 306 in
coaxially telescoping relationship. The biopsy needle assembly 304 has a
throw distance, which is the distance the biopsy stylet 306 travels
relative to the biopsy cannula 306 when fired, and which determines the
size or length of the specimen obtained.

[0044]The biopsy device 300 can comprise a variable throw biopsy device
having an adjustable throw distance to permit the user to select the size
or length of the specimen obtained. As illustrated herein, the biopsy
device 300 comprises an adjustable biopsy stylet 308 and a biopsy cannula
306 with a fixed extension distance. Since the length of the tissue
sample is set by the distance from the tip of the stylet 308 to the tip
of the cannula 306 when the stylet 308 has been fired, this distance can
be adjusted by extending or retracting the stylet 308. Thus, adjusting
the throw of the biopsy device 300 also adjusts the size or length of the
specimen obtained. Since the guide cannula 18 is adjustable in effective
length, it can advantageously accommodate for the adjusted length of the
biopsy stylet 308. In use, the throw distance of the biopsy stylet 308 is
set first, and then the coaxial needle assembly 10 is calibrated with the
set length of the biopsy stylet 308.

[0045]Referring to FIGS. 9A-9B, one expeditious way of calibrating the
coaxial needle assembly 10 is to insert the assembled cannula assembly 12
and throw calibrator 16, without the stylet assembly 14, over the biopsy
needle assembly 304 until the actuator assembly 302 abuts the insertion
stop 66, as shown in FIG. 9A. The throw calibrator 16 is then adjusted
along the cannula assembly 12 until the distal tip of the biopsy needle
assembly 304 and the open distal end 22 of the guide cannula 18 are in a
suitable predetermined relationship for insertion into the tissue mass,
as shown in FIG. 9B. One suitable predetermined relationship is one in
which the distal tip of the biopsy stylet 308 being flush with the open
distal end 22 of the guide cannula 18, which makes the effective length
of the cannula assembly 12 equal to the length of the biopsy stylet 308.
Another suitable predetermined relationship is one in which the distal
tip of the biopsy cannula 306 being flush with the open distal end 22 of
the guide cannula 18, which makes the effective length of the cannula
assembly 12 equal to the length of the biopsy cannula 306. Both
relationships guarantee that the tissue at the end of the guide cannula
18 will be sampled. Another suitable predetermined relationship is one in
which the distal tip of the biopsy needle assembly 304 closes the open
distal end 22 of the guide cannula 18, which insures that tissue will not
prolapse into the guide cannula 18. The coaxial needle assembly 10 is
then removed from the biopsy device 200 and the stylet assembly 14 is
reassembled to the coaxial needle assembly 10, readying it for insertion
in the tissue mass 100.

[0046]Another way of calibrating the coaxial needle assembly 10 is to
simply determine the throw distance of the biopsy device 300 and set the
effective length in accordance with the throw distance using indicia
provided on the guide cannula. This is especially effective if the
indicia directly correlate with the possible throw distances on the
biopsy device 300.

[0047]Referring to FIGS. 7A-7C, the coaxial needle assembly 10 is
illustrated within a tissue mass 100 having a lesion 200 to show the
various steps in the process of placing the coaxial needle assembly 10 at
the lesion 200 prior to using a biopsy device to obtain a tissue sample
from the lesion 200. Prior to insertion, the coaxial needle assembly 10
is calibrated with the throw distance of the biopsy device as discussed
above by moving the throw calibrator 16 along the guide cannula 18 to set
the effective length of the guide cannula 18. As shown in FIG. 7A, the
coaxial needle assembly 10 is inserted into the tissue mass 100 with the
stylet assembly 14 coaxially received by and coupled to the cannula
assembly 12, such that the stylet 48 is received within the lumen 20 and
protrudes slightly from the open distal end 22 of the guide cannula 18,
with the insertion tip 52 leading the coaxial needle assembly 10 through
the tissue mass 100.

[0048]As shown in FIG. 7B, the coaxial needle assembly 10 is positioned so
that the insertion tip 52 is at or near the lesion 200. Preferably, the
coaxial needle assembly 10 is positioned by using an imaging system. The
coaxial needle assembly 10 can be designed for enhanced visibility using
common imaging systems, such as CAT scan, ultrasonography and
mammography. For example, a portion of the coaxial needle assembly 10 can
be enhanced for ultrasound detection by forming an echogenicity
enhancement on either the guide cannula 18 or the stylet 48. Once such
enhancement is disclosed in U.S. Pat. No. 5,820,554 to Davis et al.,
incorporated herein by reference in its entirety.

[0049]As shown in FIG. 7C, once the coaxial needle assembly 10 is
positioned, the stylet assembly 14 is unlocked from the cannula assembly
12 and withdrawn from the tissue mass 100, thereby removing the stylet
assembly 14 from rest of the coaxial needle assembly 10. The stylet
assembly 14 is unlocked by rotating the stylet hub 56 relative to the
cannula assembly 12 to unscrew the rearward end flanges 42 from the screw
threads 64.

[0050]Referring to FIG. 7D, after placement of the coaxial needle assembly
10 at the lesion 200 and withdrawal of the stylet assembly 14, as
illustrated in FIGS. 7A-7C, the biopsy needle assembly 304 is inserted
through the lumen 20 of the guide cannula 18 until it meets the insertion
stop 66. Since the effective length of the guide cannula 18 has been
calibrated with the throw distance of the biopsy device 300, the biopsy
needle assembly 304 and the guide cannula 18 are in a suitable
predetermined relationship; in this case, the tip of the biopsy stylet
308 will protrude slightly from the open distal end 22 of the guide
cannula 18 into the lesion 200. This is extremely beneficial to the
technician taking the biopsy specimen as one cannot see the location of
the tip of the biopsy device 300 as it is in the tissue mass, but still
knows that the physical relationship between the cannula guide 18 and
biopsy device 300 will result in the biopsy device 300 being properly
located. This will negate the need for the technician to re-image the
location of the biopsy device 300 after insertion. It will also simplify
the taking of multiple specimens, which requires the withdrawal and
reinsertion of the biopsy device 300.

[0051]Referring to FIGS. 10-11, a coaxial needle assembly 10' according to
a second embodiment of the invention is illustrated, with like elements
being identified by like numerals bearing a prime (') symbol. The
structure and the method of using the second embodiment is substantially
similar to the structure of method of using the first embodiment, so the
discussion of the second embodiment will be limited to the differences
between the two embodiments. Whereas the throw calibrator 16 shown in
FIGS. 1-2 had a generally uniformly cylindrical proximal section 72, the
throw calibrator 16' has a protruded area 84 on the proximal section 72',
which allows for easier removal of the cannula assembly 14' from the
throw calibrator 16'. The elongated slot 76' is formed on the protruded
area 84. Additionally, indicia comprising a set of distance markings 86
is provided on the proximal section 72' adjacent the elongated slot 76'.
The distance markings 86 enable the effective length of guide cannula 18'
to be adjusted a predetermined amount, with or without the guide cannula
18' being inserted over a needle assembly of a biopsy device. The
distance markings 86 can directly or indirectly correspond to the throw
of a biopsy device, such that the distance markings 86 can be used to
calibrate the coaxial needle assembly 10 with the throw distance of a
biopsy device.

[0052]The throw calibrator 16' further comprises at least one rib 88
formed on the nose section 74 for frictionally engaging a tip protector
90, shown in FIG. 12 which is a sleeve-like device commonly used to cover
a needle assembly when not in use, and can be temporarily press fit over
the nose section 74. When the tip protector 90 is received on the nose
section 74, the spaces between adjacent ribs 88 form passageways 92
through which a sterilization fluid, such as ethylene oxide (EtO) gas,
can flow between the coaxial needle assembly 10' and the tip protector
90.

[0053]The guide cannula 18 and the stylet 48 are provided with at least
one marker for enhanced visibility using common imaging systems. As
illustrated herein, the guide cannula 18 comprises multiple spaced
markers on its exterior that are spaced at regular intervals, such as
every 1 cm, and the stylet 48 comprises a marking 96 near or at its
distal end 50', which can comprise an echogenicity enhancement as
disclosed in the Davis patent.

[0054]Referring to FIGS. 13A-13B, the stylet hub 56' is coupled with the
cannula hub 26' by a luer lock coupling, which provides a fluid-tight
coupling between the hub 26', 56' and allows the user to optionally
inject fluid through the coaxial needle assembly 10'. The distal
receiving section 60' of the stylet hub 56' comprises two opposed arms 98
which engage the flanges 42' on the cannula hub 26' to releasably fasten
the stylet assembly 14' to the cannula assembly 12'. The stylet assembly
14' is coupled or locked to the cannula assembly 12' by rotating the
stylet hub 26' relative to the cannula hub 56' until the arms 98 engage
the flanges 42', as shown in FIG. 13B.

[0055]FIG. 14 illustrates one example of a biopsy device system for the
percutaneous removal of a specimen from an area of interest within a
tissue mass 100, in which the coaxial needle assembly 10' is used in
conjunction with a variable throw biopsy device 400. The exemplary
variable throw biopsy device 400 comprises a actuator assembly 402
structurally and operably connected to a biopsy needle assembly 404 which
is used to penetrate the tissue mass 100 to obtain a biopsy sample from
an area of interest comprising a lesion 200. The biopsy needle assembly
404 includes a biopsy cannula 406 and a biopsy stylet 408 which is
received by the biopsy cannula 406 in coaxially telescoping relationship.
The biopsy needle assembly 404 has an adjustable throw distance, which is
the distance the biopsy stylet 406 travels relative to the biopsy cannula
406, to permit the user to select the size or length of the specimen
obtained. One example of a suitable variable throw biopsy device is
disclosed in U.S. Provisional Application No. 61/057,378, filed May 30,
2008, incorporated herein by reference in its entirety, in which the
position of a throw stop (not shown) is adjusted to set the throw
distance, i.e. the distance the biopsy stylet 406 can travel when fired.
Another example of a suitable variable throw biopsy device is disclosed
in U.S. patent application Ser. No. 10/908,427, filed May 11, 2005, which
is incorporated herein in its entirety.

[0056]It is understood that the coaxial needle assembly 10, 10' of the
invention could be used with a biopsy device having a coring cannula and
a non-notched stylet. In such a variation, the throw distance of the core
biopsy device would be the distance the coring cannula travels past the
stylet. The throw distance would be roughly equal to the distance the
distal edge of the coring cannula projects past the distal tip of the
stylet when fired.

[0057]The adjustable coaxial needle assembly 10 allows the user to adjust
the location of the throw calibrator 16 along the cannula assembly 12 and
maintain a predetermined correct relationship between the cannula and
stylet distal ends 22, 50 that is suitable for insertion of the coaxial
needle assembly 10 into a tissue mass. One example of a relationship
suitable for insertion of the coaxial needle assembly 10 into a tissue
mass is one in which the distal end 50 or insertion tip 52 of the stylet
assembly 12 closes the open distal end 22 of the cannula assembly 12 to
prevent tissue from entering the lumen 20. The ability to adjust the
effective length of the cannula assembly and maintain a correct
predetermined relationship between the stylet and cannula ends is
desirable because the coaxial needle assembly 10 can accommodate the
moving stylet of a variably throw biopsy device, insuring that a correct
sample size is obtained. The coaxial needle assembly 10 can also be used
with non-variable throw biopsy devices, and has the advantage of being
usable with a variety of biopsy devices having different throw distances.

[0058]While the invention has been specifically described in connection
with certain specific embodiments thereof, it is to be understood that
this is by way of illustration and not of limitation, and the scope of
the appended claims should be construed as broadly as the prior art will
permit.